Under normal circumstances, common micro-channel heat exchangers are flat and rectangular. However, in order to improve the heat exchange performance and satisfy different application and installation requirements, micro-channel heat exchangers are also manufactured to be in an A-shaped structure.
Due to limitation of dimension of production equipment especially a brazing furnace, micro-channel heat exchangers are usually brazed while passing through the furnace in the form of flat rectangle, and then are bent after completion of brazing to form corresponding bending angles.
Chinese patent application No. 201310681338.3 discloses a bent heat exchanger and a method for bending a heat exchanger. The bent heat exchanger comprises a first header pipe, a second header pipe, a plurality of fins and a plurality of flat pipes, each of the flat pipe comprises a first portion, a second portion and a middle portion which is connected with the first portion and the second portion, the first portion and the second portion are respectively in contact with the fins, the middle portion comprises a first twisting portion connected with the first portion and a flat straight portion connected with the second portion, the flat straight portions of these flat pipes are sequentially and partially overlapped and sequentially and closely adjoined to one another, the flat straight portion comprises an inner surface and an outer surface, and the inner surfaces and outer surfaces of these flat straight portions are flat on the whole. Although this structure can guarantee bending accuracy, since heat exchange tubes are directly bent, consequently outer sides of the bent heat exchange tubes are greatly drawn, outer walls of the heat exchange tubes become thin, the pressure resistance and corrosion resistance are influenced, the tiny channels in the heat exchange tubes are very easily deformed, and the overall performance and the service life of the heat exchanger are influenced.